<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <p>用户的名字是：{{username}}</p>
        <input type="text" v-model="username">
        <hr>
        <input type="text" :value="username">
        <hr>
    
     
      <select v-model="city">
          <option value="">请选择城市</option>
          <option value="1">北京</option>
          <option value="2">上海</option>
          <option value="3">广州</option>
      </select>
    </div>

    <script src="./lib/vue-2.6.12.js"></script>
  
    <script>
      
        const vm = new Vue({
          
            el: '#app',
           
            data: {
                username: 'zhangsan',
                city:''
            }
        })
    </script>
</body>

</html>